Landscape Genetics of Highly Disturbed Arable Systems: Insights Gained from Investigating a Small Mammal Species

Abstract

A large proportion of the earth's surface is dedicated to food production, and agriculture is widely acknowledged to influence local biodiversity via habitat loss and degradation.  Landscape genetics is an emerging field which can provide detailed understanding of how wildlife populations are influenced by landscape configuration and composition but the approach is yet to be fully integrated with agroecology.  When addressing landscape genetics questions, small mammals may provide insight; they may act as model organisms, they are abundant, they are relatively easy to sample and they may have important ecological roles within arable ecosystems.  This thesis merged the study of arable landscapes, landscape genetics and small mammals, to develop what is known about the landscape genetics of wild species in this dynamic habitat type.  To decide upon a study organism, small mammals were surveyed at an example arable field site.  Wood mice (Apodemus sylvaticus) were found to be the most abundant species and a microsatellite marker multiplex was developed for genotyping individuals.  Two aspects of their landscape genetics in arable habitat were investigated.  First, the possibility of temporal patterns in fine scale genetic structure of arable populations was explored, since this had not been investigated previously.  Next, inter-population genetic differentiation was examined to determine whether arable habitat acted as a barrier to gene flow for this species.  At the fine scale, three genetically distinct clusters of wood mice were identified and temporal variation in the spatial pattern was confirmed.  There was no evidence that arable habitat acted as a barrier to gene flow for this species in comparison to populations in urban habitat, which showed significant differentiation.  It is hoped that the landscape genetic insights provided by this thesis will encourage greater momentum for conducting landscape genetics studies in agricultural habitat.